scholarly journals Prevention of H-Aggregates Formation in Cy5 Labeled Macromolecules

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Kang ◽  
Oliver Kaczmarek ◽  
Jürgen Liebscher ◽  
Lars Dähne
Keyword(s):  
Quantitative Determination ◽  
Organic Solvents ◽  
Conformational Changes ◽  
Fluorescence Spectra ◽  
Cyanine Dye ◽  
Inhomogeneous Distribution ◽  
Aggregate Formation ◽  
Absorption And Fluorescence Spectra ◽  
Covalent Linkage

H-aggregates of the cyanine dye Cy5 are formed during covalent linkage to the cationic macromolecule Poly(allylamine) (PAH). The nonfluorescent H-aggregates strongly restrict the usage of the dye for analytical purposes and prevent a quantitative determination of the labeled macromolecules. The behavior of the H-aggregates has been studied by investigation of the absorption and fluorescence spectra of the dye polymer in dependence on solvent, label degree and additional sulfonate groups. H-aggregate formation is caused by an inhomogeneous distribution of the Cy5 molecules on the polymer chain. The H-aggregates can be destroyed by conformational changes of the PAH induced by interactions with polyanions or in organic solvents. It has been found that the polymer labeling process in high content of organic solvents can prevent the formation of H-aggregates. The results offer a better understanding and improvement of the use of the Cy5 dye for labeling purposes in fluorescence detection of macromolecules.

Fluorescence Spectra and Determination of the Energy of O-O Transitions of Coumarins in Liquid Solutions

1990 ◽  
Vol 45 (5) ◽  
pp. 618-622 ◽  
Author(s):  
A. Bączyński ◽  
P. Targowski ◽  
B. Ziętek ◽  
D. Radomska
Keyword(s):  
Fluorescence Spectra ◽  
Room Temperature ◽  
Optical Transition ◽  
Solvent System ◽  
Absorption And Fluorescence Spectra ◽  
Initial State ◽  
Liquid Solutions ◽  
Analytical Expressions ◽  
Electronic Transition Energies

Abstract Analytical expressions of absorption and fluorescence spectra of some coumarins in ethyl alcohol at room temperature are given. Satisfactory agreement of measured and calculated spectra is obtained. It was possible to obtain the pure electronic transition energies immediately after excitation (from absorption spectra) and after the thermal and orientational equilibrium is reached (from fluorescence). An optical transition carries a dye-solvent system to a state in which the mutual interaction energy is larger than in the initial state

Fluorometric Properties of N-Methyltetraphenylporphine and Several Derivatives: Evaluation as Standards for Determination of Chlorophyll Concentrations

1982 ◽  
Vol 36 (4) ◽  
pp. 430-435 ◽  
Author(s):  
David K. Lavallee ◽  
Thomas J. McDonough ◽  
Lisa Cioffi
Keyword(s):  
Chlorophyll A ◽  
Organic Solvents ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Quantum Yields ◽  
Polar Organic Solvents ◽  
Solvent Systems ◽  
Nonpolar Organic ◽  
Chlorophyll Concentrations

As part of an ongoing study of the chemistry and properties of N-methylporphyrins and their metal complexes, we have observed that the excitation and emission spectra of N-methyltetraphenylporphyrin and N-methyltetra( p-sulfophenyl)porphyrin and their zinc complexes closely resemble corresponding spectra of chlorophyll a. We have characterized fluorescence spectra for these species in a variety of solvents commonly used for quantitative determination of chlorophylls. Quantum yields for the N-methylporphyrins are lower by approximately a factor of 10 than yields for chlorophyll a in such solvents as acetone, ethanol, and mixed aqueous/organic solvent systems. The yields are quite sufficient, however, for these species to be used as fluorescence standards. Solution of N-methylporphyrins are stable and the compounds can be inexpensively synthesized in high purity. The tetra( p-sulfophenyl) species are soluble in aqueous and highly polar organic solvents, whereas the tetraphenyl species are soluble in nonpolar organic solvents.

SIZE EFFECT OF CYANINE DYE J-AGGREGATES IN MICROMETER-SIZED POLYMER "DOMES"

2002 ◽  
Vol 01 (05n06) ◽  
pp. 461-464 ◽  
Author(s):  
OLAF KARTHAUS ◽  
KIYOSHI OKAMOTO ◽  
RYOTA CHIBA ◽  
KAZUAKI KAGA
Keyword(s):  
Fluorescence Microscopy ◽  
Size Effect ◽  
Fluorescence Spectra ◽  
Cyanine Dye ◽  
Absorption And Fluorescence Spectra ◽  
Dewetting Process ◽  
Glass Substrates ◽  
J Aggregates ◽  
Dye Solutions

The fluorescence behavior of 3,3′diethyl-thiacarbocyanine iodide in micrometer-sized polystyrene droplets, or "domes" on glass substrates was investigated. The samples were prepared by casting dilute polymer/dye solutions onto the substrates. A dewetting process leads to the formation of small polymer domes with a diameter of 1–100 μm and a height of 100 nm to several μm. Fluorescence microscopy shows that the dye is incorporated into these polymer domes. It was found that the absorption and fluorescence spectra depend on the size of the polymer domes. Larger domes show red-shifted fluorescence spectra.

Sign in / Sign up

Export Citation Format

Share Document